function validateFields(fieldsArray) {
    const errors = []
    let selectedGroup

    const numberRegex = /^[+]?([.]\d+|\d+([.]\d+)?)$/
    const emailRegex =
        /(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9]))\.){3}(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9])|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/
    const dateRegex = /^\d{4}\-(0?[1-9]|1[012])\-(0?[1-9]|[12][0-9]|3[01])$/
    const timeRegex = /^\d{1,2}:\d{2}-\d{1,2}:\d{2}$/
    const phoneRegex = /^\s*(?:\+?(\d{1,3}))?[-. (]*(\d{3})[-. )]*(\d{3})[-. ]*(\d{4})(?: *x(\d+))?\s*$/

    const wholeBlockInvalid = () => {
        const blockContainer = document.getElementsByClassName("blockContainer")[0]
        blockContainer.classList.add("invalidBlocks")
    }

    const validateNumber = (value, field, element) => {
        if (!numberRegex.test(`${value}`)) {
            errors.push(["block", () => element.classList.add("border-red")])
        }
    }

    fieldsArray.forEach(([field, value]) => {
        if (field === "blockGroups" || field.includes("numberLabel")) {
            if (!field.includes("numberLabel")) return
            const [elementValue, element, group] = value

            if (!elementValue) return

            if (selectedGroup !== undefined) {
                if (group !== selectedGroup) {
                    errors.push(["block", wholeBlockInvalid])
                } else {
                    validateNumber(elementValue, field, element)
                }
            } else {
                selectedGroup = group
                validateNumber(elementValue, field, element)
            }
            return
        }

        if (!value) {
            errors.push(["Eingabe ist erforderlich.", field])
        } else if (field.includes("number_")) {
            if (!numberRegex.test(`${value}`)) {
                errors.push(["Ungültiger numerischer Wert.", field])
            }
        } else if (field.includes("agreement_")) {
            if (value !== true) errors.push(["Bitte das Kontrollkästchen anklicken.", field])
        } else if (field.includes("Email_")) {
            if (!emailRegex.test(value)) errors.push(["Ungültiges E-Mail-Format.", field])
        } else if (field.includes("date_")) {
            if (!dateRegex.test(value)) errors.push(["Ungültiges Datumsformat.", field])
        } else if (field.includes("times_")) {
            if (!timeRegex.test(value)) errors.push(["Ungültiges Zeitformat.", field])
        } else if (field.includes("Telefon_")) {
            if (!phoneRegex.test(value)) errors.push(["Ungültiges Telefonnummernformat.", field])
        }
    })

    return errors
}

module.exports = {
    validateFields,
}